Montmorillonites supported with metal oxide nanoparticles for decontamination of sulfur mustard

Abstract

The montmorillonites supported with MgO, MnO2, Fe2O3, CoO, NiO, CuO, ZnO, CeO2, and Ag2O nanoparticles were made by ion exchange, precipitation, and successive calcination. Prepared solids were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy-dispersive analysis of X-rays, nitrogen adsorption, and gravimetric techniques. X-ray diffraction data depicted the maintenance of the host structure during synthesis of montmorillonites supported with metal oxide nanoparticles. It also indicated the presence of crystallites of MnO2, Fe2O3, CuO, ZnO, CeO2, and Ag2O metal oxide nanoparticles on the respective montmorillonite supported materials. The absence of corresponding diffraction peaks of MgO, CoO, and NiO metal oxide nanoparticles in the respective montmorillonite supported materials indicated that the concentration of the crystalline nanoparticles was low on the surface. Transmission electron microscopy data indicated the formation of metal oxide nanoparticles of size varying from 2 to 11nm on the external surface of montmorillonites. Significant decrease in the values of specific surface area and pore volume indicated the partial blocking of pores of montmorillonites by metal oxide nanoparticles. These materials were used for decontamination of sulfur mustard. Montmorillonite supported Ag2O nanoparticles demonstrated superior decontamination efficiency against sulfur mustard. It chemically degraded 100% of sulfur mustard within 2h, whereas other materials took up to 16h to completely degrade the same. Bare montmorillonite displayed least decontamination efficiency among all materials toward sulfur mustard. It decontaminated only 90% of sulfur mustard in 24h.